Anionic Rhodium Complexes as Very Active Catalysts for Hydro-Silylation Reactions

Four anionic rhodium complexes were synthesized using RhCl3 as a precursor. All derivatives were isolated and characterized spectroscopically (NMR, ESI-MS). For one of them, [BMPip][RhCl4], the crystallographic structure was determined. Additionally, their melting points and thermal stabilities were established. The obtained derivatives were used as catalysts for the hydrosilylation of two olefins with various properties. All tested catalysts were insoluble in the reaction medium, which permitted their easy isolation and repeated use in subsequent catalytic cycles. The most effective catalyst did not lose its activity, even after fifty cycles of hydrosilylation of octene using heptamethyltrisiloxane (HMTS).